Write the sum using summation notation, assuming the suggested pattern continues. -3 + 6 + 15 + 24 + + 132

Common difference is +9
Initial value is -3
Range of index numbers is 1-16

You can find sum notation of the question by using arithmetic series,
a(n) = a(1) + d*(n-1) = -3 + 9*(n-1) = 9n - 12 is the general term of the series